Apparatus for the continuous casting of flat blooms



July 28; 1970 P. COLOMBO APPARATUS FOR THE CONTINUOUS CASTING OF FLATBLOOMS Filed Jan. 26, 1968 INVENTOR COL OMB 0,

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P/EEO United States Patent Int. Cl: B22d 11/10 US. Cl. 164-281 3 ClaimsABSTRACT OF THE DISCLOSURE In a flat blooms continuous casting plant,the tundish is mounted so as to be reciprocated with respect to theunderlying open ended mold in the direction of the major sides of saidmold. Means are provided for reciprocating the tundish during thecasting of the molten metal into the mold.

This invention relates to the continuous casting of metals, and moreparticularly to an apparatus for the continuous casting of flat steelblooms.

In the continuous casting of metals in form of flat blooms a mainproblem 'arises connected with the difliculty of obtaining an evendistribution of the temperatures inside the continuous casting mold,particularly in the direction of the longer sides of the cross-sectionof the bloom. -In fact, it is known that in the continuous casting ofmetals, the mold, which is open ended, is fed with the liquid metal froma fixed tundish, disposed above the mold and provided at its bottom withone or more pouring nozzles from which the molten metal flows from thetundish into the mold. As a consequence, in the known continuous fiatblooms casting apparatus the streams of molten metal from the tundishare always flowing towards fixed locations inside the mold, thus givingrise to an uneven distribution of the temperatures inside the ascastbloom, with overheated zones in correspondence of the pouring nozzlesand particularly along the long sides of the bloom itself.

On the other hand, it is not possible to obviate to the saiddisadvantage by increasing the number of the pouring nozzles, or bydecreasing the mutual distance between the said nozzles, as it would beprima facie obvious, because of the fact that the number of allowablenozzles and/or the interdistance between contiguous nozzles are afunction of other parameters of the said apparatus and cannot be variedat will, as it is well known to any person skilled in the art to whichthe present invention appertains.

The said uneveness in the temperatures distribution, which are as moreappreciated as greater the ratio between the long and short sides of thecross section of the fiat bloom is, give rise to crackings on thesurface of the fiat bloom. The side cracks formation is particularlyevident whenever steels having a low thermal conductance and a low yieldpoint at high temperatures are cast.

Moreover, the said localized hot zones may also conduct to the burst ofthe skin of the cast bloom, with consequent escape of molten metal fromthe core of the bloom, or to bulking of the bloom sides, by effect ofthe ironstatic pressure acting on the hot zones of the bloom skin.

It is therefore the main object of the present invention to obviate tothe above mentioned disadvantages of the known fiat blooms castingapparatus.

According to the present invention, the above object is accomplished byreciprocably mounting the tundish in a substantially horizontal plane,so as to effect a to and fro movement in the direction parallel to thedirection of the longer sides of the underlying open ended casting mold,means being provided for reciprocating the tundish during the castingoperation.

By the said arrangement, the position of the molten metal streamsissuing from the pouring nozzles at the bottom of the tundish varies,during the casting operation, continuously along the direction of thereciprocating movement of the tundish, and thus parallel to the longsides of the mold. In this manner, by suitably selecting the amplitudeand the frequency of the said reciprocating movement with respect to thenumber and the interdistance of the pouring nozzles at the tundishbottom, and with respect to the cross sectional dimensions of the flatbloom which is being cast, a substantially even distribution of thetemperatures in the cast bloom is obtained, thus obviating to the abovementioned drawbacks.

The above and other objects and advantages of the present invention willbe better apparent from the following specification, made with referenceto the accompanying drawing, in which:

FIG. 1 is a schematic partially sectioned side view of the reciprocatingtundish according to the invention, with the associated mold and ladleof a continuous metal casting plant, and

FIG. 2 is a top plan view of the open ended mold of the plant of FIG. 1.

In the drawings, 1 generally denotes the open ended mold of a continuousmetal casting plant of conventional construction. The said mold 1 ismounted in conventional manner on a platform 2 so as to be reciprocatedin a substantially vertical plane, in the directions of the double arrow3. The mold 1 is further provided with a jacket 4 through which acooling fluid is continuously circulated through pipes 5. In theembodiment as shown in FIG. 2, the mold 1 is of rectangular crosssection in plan view, for the continuous casting of so-called flatblooms, that is of blooms have a substantially rectangular or otherwiseelongated cross section, with two opposite sides of a lengthsubstantially greater than the length of the remaining two sides. 6denotes a pair of conventional bloom or ingot guide rolls, mounted belowmold 1 along the path of the cast flat bloom 7.

Above mold 1 the tundish 8 is mounted, which is supported on a movableframe 9, straddling the mold 1 and provided with supporting legs 10,provided at their lower ends with wheels 11, rolling on horizontaltracks 12 supported by the fixed frame (not shown) and extending in thedirection of the longer sides of the mold 1.

The tundish 8, as shown in the drawing, comprises an outer shell 81 ofsheet metal, comprising side walls and a bottom wall. The sheet metalWalls are reinforced with intermediate heavy steel plates 82, upon whichan inner lining made of refractory material slabs 83 is fitted, coveringthe sides and the bottom of the tundish 8. On the bottom of the tundish8 a pair of pouring nozzles 13 are mounted, through which the moltenmetal from tundish 8 flows into the underlying mold 1. Above the tundish8, the molten metal pouring ladle 14 is suspended, in conventionalmanner.

In correspondence of one of the smaller sides of the tundish-supportingframe 9, between a pair of lugs 16 connected to one of the legs 10 ofsaid frame a connecting rod 15 is hinged by one of its ends. The otherend of said connecting rod 15 is hinged to a crankpin 17 fited onto thefly wheel 18 keyed on the output shaft 19 of a speeddown gear 20, theinput shaft of which is driven by a suitable motor (not shown).

The operation of the just described apparatus is as follows:

When the molten metal has been poured from the ladle 14 into the tundish8, by rotating the wheel 18, through crankpin 17 and connecting rod 15the frame 9 is slowly reciprocated on rails 12 and the tundish 8 isreciprocated over the mold 1 in the direction of arrows 21, that is inthe longitudinal direction of the said mold 1. By this horizontalreciprocating movement, the molten metal, in the tundish 8, flows outthrough nozzles 13 into the underlying vertically reciprocated mold 1substantially along its Whole length, thus avoiding the formation of hotpouring zones in said mold and producing a practically homogeneous flatbloom, which is cast from the underside of the mold 1.

It is thus apparent that by the above arrangement the mentioneddrawbacks connected with the continuous casting of fiat blooms areobviated.

Having thus fully described my invention with reference to a preferredembodiment thereof, what I claim as new is:

1. A continuous metal casting apparatus for the continuous casting offiat blooms, comprising a fixed supporting frame, an open ended moldcarried by said fixed frame, a tundish supported by said fixed frame anddisposed above said mold, and pouring nozzles in the bottom of saidtundish for pouring the molten metal from said tundish into said mold;the improvement consisting in supporting said tundish movable toand-froin a substantial horizontal direction above said mold, and automaticmeans for continuously reciprocating said tundish during metal pour soas to cause its pouring nozzles to reciprocate above said mold cavity onlongitudinal paths substantially parallel to the major axis of the crosssection of the flat bloom being cast in such a manner that asubstantially even distribution of temperatures in the cast bloom isobtained.

2. A continuous metal casting apparatus for the continuous casting offiat blooms comprising a supporting frame, a mold platform, a verticalgravity flow open ended mold on said platform; said mold being providedwith two parallel sides of a greater length than the length of theremaining two sides; guide rails on said frame extending in a horizontalplane and in a direction which is substantially parallel to thedirection of the said longer sides of the said mold; a wheeled frame onsaid rails supported for a movement along said mold; a tundish on saidframe above said mold; pouring nozzles in the bottom of said tundish;and operating means connected to said tundish supporting frame forreciprocating said frame and tundish above said mold along said guiderails.

3. A continuous casting plant according to claim 2 in which saidoperating means comprise a crank and connecting rod transmission, saidconnecting rod being hinged by one end to the crankpin and by itsopposite end to said wheeled frame.

References Gited UNITED STATES PATENTS 612,610 10/1898 Levy 164-1363,456,713 7/1969 Michelson 164-82 1,298,036 3/1919 Gathmann 1641352,732,601 1/1956 Junghans 16482 3,375,862 4/1968 Boitchenko et al.164-281 X 3,435,879 4/1969 Greenberger 16483 FOREIGN PATENTS 515,2438/1955 Canada.

I. SPENCER OVERHOLSER, Primary Examiner R. S. ANNEAR, Assistant ExaminerUS. Cl. X.R. 164-136

